Filter holder



FIG. 1 is a perspective view of a filter holder showing my new design;

FIG. 2 is a side elevational view thereof, the opposite and adjacent sides being substantially the same in appearance;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a vertical sectional view thereof, taken along line AA of FIG. 3. 

The ornamental design for a filter holder, as shown and described. 